As a result of the continuous long strides of progress in technology, material civilization and electronic industry, all the high buildings, restaurants, hotels, banks, hospitals, grocery stores, department stores, factories and warehouses have used automatic doors to keep the air-conditioned temperature, to prevent the air therein from convection, to keep the noise from entering into the room, and to facilitate people to pass through the door quickly.
Almost all the conventional doors being used in a building or the like have a common problem, i.e., lacking of repair and maintenance. The normal wear and tear or the damages caused by the sparks (because of the existing conventional automatic doors using electric parts) would cause the doors to have minor troubles, such as the micro-switch that controls the motor does not turn off, or any obstacle is placed on the rail to stop the door to run. Any one of the aforesaid minor troubles would cause the control circuit and the motor not to operate normally. Finally, these minor troubles may damage the motor or the control circuit after a period of running under an overload condition, and a fire may be resulted thereby. The aforesaid examples are known by the inventor due to his experiences in making, installing and repairing the automatic doors for many years. In view of the aforesaid experiences, the inventor has developed an automatic door, which is to be controlled with a servo-controlled safety protection device so as to obviate the aforesaid drawbacks in the conventional automatic doors.